1. Field of the Invention
The present invention relates to the connecting of external items to a subsea structure. More particularly, the present invention relates to collet-type connection systems. More particularly the present invention relates to the ability to connect hubs through the use of a collet system.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Technology advances related to subsea petroleum exploration have resulted in the development of various conduit and wellhead connector mechanisms which may be remotely controlled for the purpose of achieving connection between mechanical and hydraulic apparatus of wellheads, conduits, and the like. A popular type of connector assembly is a hydraulically-actuated collet connector which utilizes a series of segment clamps which are biased by other mechanical apparatus to releasably secure a pair of abutting flanges into a sealed assembly. Collet connectors and other acceptable connector mechanisms are generally utilized for connection of the wellhead valve system with the production system of the wellhead so that the wellhead valve assembly may be disconnected and removed in the event that replacement or repair is necessary.
A multi-well subsea assembly can include subsea structures such a subsea trees, manifolds, and/or pipeline end terminations. These subsea structures can be interconnected by jumpers. The jumpers mate up with the subsea structures using connectors that mate with hubs on the subsea structures. Production is often routed from the trees in the gathering manifolds and from the gathering manifolds to pipeline end terminations and pipelines to the platform.
When dealing with subsea applications, it becomes necessary to simplify or eliminate the use of divers during the locking of a connector in order to secure the connection between the drilling or piping components in the wellhead. Hydraulically-actuated collet connectors have been developed and utilized for this purpose. These collet-type connectors are designed for high pressure in deepwater drilling operations. The collet connectors are secured over the mating sections of the drilling or piping components to be connected by use of hydraulic pressure. Because the hydraulic pressure can be controlled remotely, it is not necessary for divers to lock the collet connector in order to secure the connection.
There are several problems associated with existing collet connectors. First, and foremost, very skillful operators are required so as to bring the hub of a collet connector into a proper position with respect to the hub of the subsea structure. In certain circumstances, it is been known that the hubs can become damaged if the landing between the hubs is not carried out properly. Additionally, there is a possibility that the gasket between the hubs can become compromised if an improper engagement between the hubs is carried out. Additionally, in prior art collet connectors, the lead screw associated with the collet connectors is placed into the primary load path of the connection. As a result, additional force is required in order to achieve the proper connection. In prior art collet connector systems, it becomes difficult for the operators to properly view the connection while it is being carried out. Furthermore, prior art collet connector systems also have ineffective secondary removal capabilities. As such, a need has developed in association with collet connectors so as to allow the collet connector to be easily and properly installed with no possibility of damaging contact during the installation.
In the past, various patents and patent application publications have issued with respect to collet-type connectors. For example, U.S. Pat. No. 3,523,579, issued on Aug. 11, 1970 to N. A. Nelson, describes a wellhead valve assembly which includes a plurality of hydraulically-actuated valves and an appropriate hydraulic fluid supply system for actuation of the valves. A hydraulically-actuated collet connector is provided for connecting production flow conduits and hydraulic fluid supply conduits to the wellhead valve assembly. The collet connector includes a means for remotely detecting leakage of production fluid or hydraulic fluid in the event that the joint between the wellhead valve assembly and the hydraulic collet connector should fail to properly seal.
U.S. Pat. No. 4,477,105, issued on Oct. 16, 1984 to Wittman et al., teaches a collet-actuated ball-and-socket connector. This connector is for connecting the ends of two pipes. A ball coupling member is adapted for connection to the end of one of the pipes. A retaining flange is freely disposed about the ball coupling member and engages the outer surface of the member. A socket coupling member is adapted for connection to the end of the other of the two pipes and provided for accepting the ball coupling member so as to provide a metal sealing ring for mating with the ball members. A collet locking means is mounted about the outer periphery of the socket coupling member and extends generally axially therefrom for permitting insertion of the ball coupling member in mating engagement with the socket coupling member when the collet means is open. An actuating means applies a predetermined axial force to the collet locking means for closing the collet means to engage the retaining flange and lock the ball-and-socket coupling members together in a sealed rigid relationship.
U.S. Pat. No. 4,693,497, issued on Sep. 15, 1987 to Pettus et al., describes a remotely-actuated collet connector which is suitable for joining tubular members with similar or different end preparations or profiles. The collet connector includes a housing to support the connector from a first tubular member, a plurality of collet fingers or segments mounted within the housing and around the exterior of the first tubular member, and an actuator ring surrounding the fingers to move the fingers to a release or latch position, and a pressure responsive means for moving the actuator ring. Each of the collet fingers has a first engaging surface and an adapter secured to the finger and also has a second engaging surface. The first engaging surface mates with the end profile of the first tubular member. The second engaging surface mates with the end profile of the second tubular member so that when the collet fingers are moved to the latch position they secure the first and second tubular members together.
U.S. Pat. No. 4,708,376, issued on Nov. 24, 1987 to Jennings et al., shows a collet-type connector having an upper body member having a plurality of collet segments, a cam ring movable relative to the upper body member to move the collet segments into a detachable connection with the connector of a subsea wellhead. The cam ring and the collet segments have sets of camming surfaces whereby a first set is cooperative to pivot the collet segments initially toward the wellhead and whereby a second set serves to urge the collet segments further to clamp the connector to the subsea wellhead. When the second set of camming surfaces function, the first set no longer functions to rotate the collet segments so as to reduce the power requirements for urging the collet segments into clamping engagement.
U.S. Pat. No. 6,267,419, issued on Jul. 31, 2001 to Baker et al., shows a remotely actuated clamping connector. The clamping connector includes clamp halves linked by a locking stem. The locking stem is forced into a pre-stressed state by moving the locking stem from a first relaxed position to a second pre-stressed position and retained in the second pre-stressed position by a locking collet. A locking collet through which the locking stem extends is moved from a first unlocked position to a second locked position wedged between the locking stem and one or the other of the clamp halves. When the locking collet is in the second locked position, it resists movement of the locking stem from the second pre-stressed position to the first relaxed position. The locking collet is then locked in the second locked position.
U.S. Patent Application Publication No. 2014/0361534, published on Dec. 11, 2014 to K. Bekkevold, describes a connector having a plurality of latching fingers arranged around a cylindrical body and having a central axis. Each finger has a first end region extending beyond an end of the body includes a first latching structure. Each finger is pivotally supported at an intermediate region by a portion of the body and is movable between a non-latching position and a latching position in which the first end region is closer to the central axis than in the non-latching position. The connector includes a first actuated member arranged in contact with a plurality of fingers and operable to move the fingers between the non-latching position and the latching position. An actuator is operable to force a second end region of each finger toward the body. The connector can be connected to a hub by bringing the connector face into contact with a hub face, moving the latching fingers toward the connector until the first latching structures are engaged in corresponding second latching structures on the hub, and then holding the latching structures together in a latching engagement.
It is an object of the present invention to provide a collet connection system that effectively prevents damage to the hubs and damage to the gasket that is arranged between the hubs.
It is another object the present invention provide a collet connection system that improves installation efficiency.
It is another object the present invention to provide a collet connection system that allows less skillful operators to carry out the connection.
It is another object of the present invention to provide a collet connection system in which the travel of the collet connector can be viewed externally.
It is another object of the present invention to provide a collet connection system that facilitates secondary removal capabilities.
It is a further object of the present invention to provide a collet connection system that takes the lead screw out of the primary load path.
It is another object of the present invention to provide a collet connection system that allows less torque to be used for the connection process.
It is still a further object of the present invention to provide a collet connection system that effectively preloads the hub to the hub connector.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.